Why Do Fruit Trees Bloom in Autumn? Causes and Prevention Methods

Autumn blooming in fruit trees not only affects the following year's yield, but also consumes the tree's nutrients and weakens its vigor, which is very unfavorable for the trees' overwintering.

I. Causes of Autumn Blooming

First, different varieties have different adaptability to external environmental conditions. When summer and autumn bring high temperatures and drought without timely irrigation to combat the drought, fruit trees absorb less nitrogen nutrition, their growth vigor weakens, and vegetative growth is poor. At this point, for fruit tree varieties prone to stress responses to external drought, the plant's growth center begins to shift from vegetative growth to reproductive growth, increasing the likelihood of autumn blooming.

Second, improper orchard management can easily lead to autumn blooming. In orchards with improper pruning and shaping, chaotic canopy structure, many upright vigorous branches, and uneven shoot growth, the canopy's ventilation and light penetration conditions are poor, which easily causes massive leaf drop. Because of early leaf drop, the tree's nutrient storage level declines, leading to poor flower bud differentiation, and some enter dormancy early, triggering a second bloom in autumn. Some orchards apply heavy chemical fertilizers without applying, or applying little, organic fertilizer, or without applying post-harvest fertilizer, resulting in poor tree vigor, which likewise causes massive leaf drop and promotes the phenomenon of a second bloom.

Third, pests and diseases. Fruit trees such as pear, peach, and plum have many types of pests and diseases. If control timing is improper or no control is applied, it often leads to massive leaf drop in the orchard and early entry into dormancy. When rainfall is plentiful in September to October and the climate is suitable, autumn blooming occurs.

Fourth, weather factors. Abundant summer rainfall and waterlogging affect the growth and absorption of fruit tree roots, weakening tree vigor. If high temperatures and drought occur again in autumn, it easily leads to massive leaf drop and a second bloom in the orchard. If conditions similar to the warm spring climate occur in October to November and soil nitrogen and water supply are sufficient, flower buds are extremely likely to sprout and produce off-season flowers.

II. Preventive Measures

To prevent autumn blooming in fruit trees, the following measures can be taken:

First, apply heavy organic fertilizer to enhance tree vigor. According to the growth characteristics of fruit trees such as peach and pear, fertilization should be timed to the flower bud differentiation period, mainly with quick-acting nitrogen fertilizer, combined with phosphorus and potassium fertilizer; during the fruit tree growth period, timely fertilization and foliar fertilizer spraying should be carried out according to growth needs to enhance tree vigor.

Second, rational irrigation. Open good drainage ditches for low-lying orchards, and promptly drain standing water when there is heavy summer rain; during autumn drought, carry out timely drought relief to protect leaves and promptly spray foliar fertilizer.

Third, do a good job in pest and disease control. During the fruit tree growth period, ensure pest and disease control at key time points and spray pesticides promptly; after leaf drop and before spring bud break, prune diseased and pest-infested branches, overly dense branches, and excessive vigorous branches, remove diseased and pest-infested fruit, and sweep up fallen leaves, burn them in a centralized manner and bury the ashes deeply; after leaf drop in winter, spray 1 time with 3 to 5 degrees Baumé lime sulfur mixture to reduce the pest and disease base.

Fourth, handling of a second bloom. If this situation occurs on vigorous trees and only a small amount of blooming occurs in autumn, and the impact on tree vigor is not significant, it can be left to take its natural course. For those with too many flower buds, measures to control growth should be taken, otherwise it will consume a large amount of nutrients, weaken tree vigor, and be unfavorable for overwintering as well as for improving the fruit-setting rate the following year.

Song Suzhi Chai Quanxi